Documentation: remove duplicated words

Remove many duplicated words under Documentation/ and do other small
cleanups.

Examples:
        "and and" --> "and"
        "in in" --> "in"
        "the the" --> "the"
        "the the" --> "to the"
        ...

Signed-off-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/filesystems/directory-locking b/Documentation/filesystems/directory-locking
index 34380d4..d7099a9 100644
--- a/Documentation/filesystems/directory-locking
+++ b/Documentation/filesystems/directory-locking
@@ -82,7 +82,7 @@
 
 	Consider the object blocking the cross-directory rename.  One
 of its descendents is locked by cross-directory rename (otherwise we
-would again have an infinite set of of contended objects).  But that
+would again have an infinite set of contended objects).  But that
 means that cross-directory rename is taking locks out of order.  Due
 to (2) the order hadn't changed since we had acquired filesystem lock.
 But locking rules for cross-directory rename guarantee that we do not